1. Field of the Invention
The present invention relates generally to grade alignment devices used in construction. More particularly, the present invention relates to a reversible alignment system for motor grader blades and the like. Known prior art may be found in U.S. Classes 94, 172, 404 and the various subclasses thereunder.
2. Description of the Prior Art
As will be recognized by those skilled in the art, construction at large projects is often difficult and requires special considerations. In particular, it is often difficult to build roads and the like that conform to established specifications. To assist those working on such projects, string lines or other reference points are normally erected at the site.
However, such references are often difficult for operators of large, earth-moving equipment such as motor graders to rely upon during normal operations. Several complicated prior art devices have been proposed to address this issue. For example, U.S. Pat. No. 3,514,630 issued to Steele shows an add-on leveling unit which is an accessory to a paving machine that provides a reference to the observer. Another, U.S. Pat. No. 3,637,026, shows automatic valves, etc., that are actuated by a probe that follows a conventional string line. This device uses numerous probes all at once and provides complex differential elevation control.
U.S. Pat. No. 3,791,753, shows an "elevation sensing device" 77 in FIGS. 7 & 8 of the drawings that is also discussed in Columns 5, lines 45-55. U.S. Pat. No. 4,403,889, shows an optical way of using a string line for a reference. It provides a visible warning to the operator when the operating the device. U.S. Pat. No. 4,948,292, uses a string line sensing system 80 in combination with a projecting ball at one end that actuates automatic apparatuses. Another interesting device is shown in U.S. Pat. No. 3,540,360, with a the string line apparatus 100 that includes the visible elements 108 and 112 that operates mechanical devices. U.S. Pat. No. 2,844,882, shows an automatic level control that references the string line as well. U.S. Pat. Nos. 3,249,026, 3,511,949 and 2,907,398 all show similar devices.
These devices are all somewhat complicated and they are generally designed to be permanently installed on the vehicle. Moreover, since some require special adaptation and the like, they are often difficult to retrofit to existing machinery without significant modifications. Such modifications often hamper the equipment's normal use or otherwise prevent its convenient use. Consequently, the known prior art fails to provide an economical and efficient, retrofittable guidance system for earth-moving equipment that maintains the equipment's original operational parameters.
A desirable system should enable the operator to easily comply with construction specifications by using conventional reference guides such as string lines or the like. Furthermore, it should enable the operator to fully utilize the machinery as intended without hampering the machinery during normal operations. Preferably, such an improved system would require minimal alterations to the original equipment to preserve the equipment's operational parameters.
One important feature lacking in the known prior art is a quickly reversible alignment system that would enable the operator of a motor grader or the like to utilize both the left and right hand sides of the vehicle equally. While some prior art devices employ structure that enables both sides of the vehicle to be used, they generally entail doubling the working structures involved with the device. Such duplication entails larger initial expenses as well as higher maintenance and more frequent down time caused from breakdowns. A better approach would be to provide an easily reversible system that required minimal set-up time and little operator training to employ. Such a system would cut initial costs while decreasing maintenance costs and down time during use.
Thus, a quickly reversible alignment system that permitted convenient transfer from the left to the right side of the vehicle would be desirable. A system that required minimal tools and operator training would also be beneficial.